The purpose of this shared instrumentation grant is to obtain funds to purchase a confocal laser scanning light microscope to be used principally by a group of investigators in the Department of Molecular Biology at the Research Institute of Scripts Clinic. The Department now contains a large group of investigators studying diverse problems of organelle structure, dynamics and function. These projects involve the plasma membrane and intercellular junctions, endosomes, the endoplasmic reticulum and membrane trafficking, interphase nd mitotic microtubule arrays, the nuclear envelope, and components involved in the regulation of the cell cycle. These studies require localization of specific components of cells and tissues during different functional states at high resolution by immunofluorescence and other light microscope techniques. The projects would all markedly benefit from the substantially increased resolution, clarity and definition of images that can be provided by the laser scanning confocal microscope.